MIT spin-off Ambri is a step closer to bringing a novel liquid metal battery to the electricity grid.

The company on Thursday cut the ribbon on a new production facility in Marlboro, Mass., where it intends to make shipping-container size batteries. Ambri also said its first two customers will be a military base on Cape Cod, in Massachusetts, and a wind project in Hawaii. The company will be making prototypes and demonstration units in Marlboro for installation next year and intends to have a full-scale manufacturing facility in 2015.

To keep battery prices low, Ambri uses inexpensive materials and a simple design. Each battery cell is a square metal box about 10 centimeters per side. (The image is a beta cell that was larger and circular.) Each cell contains two metals and a salt electrolyte that are all in liquid form when the battery is running. Because the materials have different densities, three distinct layers form. When discharging, metal ions from the top layer, which is the anode, travel through the electrolyte to combine with ions from the bottom layer, which is the cathode. The process works in reverse during charging. The battery operates at hundreds of degrees Celsius, and the heat generated by the charging and discharging keeps the internal cell components liquid.

MIT professor Donald Sadoway and his then-graduate student David Bradwell designed the first proofs of concept using antimony and magnesium with a salt electrolyte. In 2010, they formed a company, which has been funded by venture capital, energy company Total, and a Department of Energy ARPA-E grant.